The growing demand for oil from various nations around the world is resulting in higher energy prices that have the potential to increase inflation and geopolitical tensions between the nations competing for the same limited oil reserves. Even if the supply of oil could be increased to meet the demand, doing so has the further potential of producing higher CO2 emissions with the possibility of more rapid global warming.
Currently many transportation, oil, and energy companies and governments are investing billions of dollars in hydrogen related research and development programs to produce a fuel source that will gradually replace fossil fuels. For example, many car companies have been developing hydrogen fuel cell vehicles. However, fuel cell durability, efficiency, fuel purity requirements, hydrogen storage, and cost limitations are major implementation barriers.
Automakers are also developing hybrid electrical/internal combustion engine propulsion systems as a transition stage between current internal combustion engine vehicles and future fuel cell vehicles. It is unclear, however, whether hybrid electrical propulsions systems provide high enough value added efficiency benefits to consumers to justify their higher cost.
Converting existing internal combustion engine systems to operate on hydrogen is also not without problems. The combustion temperature for hydrogen is much higher than for gasoline, resulting in high amounts of NOx emissions being formed. Using lean hydrogen fuel mixtures to reduce potential NOx emissions, but also greatly reduces the power output performance levels. Direct hydrogen injection can improve this problem, but the injectors are very expensive and require high pressures and tolerances. The injection pulse provides limited amount of hydrogen fuel making it insufficient for larger power applications. The dryness of the hydrogen gas also makes it more difficult for the pulsing injectors to work and increases injector wear. Moreover, the high diffusiveness of hydrogen gas often results in the hydrogen gas passing through engine sealing systems into crank shaft regions, resulting in very undesirable combustion that can damage the engine and/or ignite the oil lubricant.